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FNA | Family List | FNA Vol. 7 | Brassicaceae | Draba

51. Draba jaegeri Munz & I. M. Johnston, Bull. Torrey Bot. Club. 56: 164. 1929.

Perennials; (densely cespitose); caudex branched (densely covered with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. Stems unbranched, (0.05-)0.15-0.5(-0.6) dm, hirsute through-out, trichomes simple, 0.1-0.8 mm, and 2-4-rayed, 0.0.5-0.4 mm. Basal leaves (densely imbricate); rosulate; sessile; blade oblanceolate to ovate, 0.4-1.5 cm × 1.5-3.5 mm, margins entire, (ciliate, trichomes simple, 0.3-1.1 mm), surfaces pubescent abaxially with stalked, (2-)4-6-rayed trichomes, 0.1-5 mm, (midvein obscure), adaxially glabrous proximally, sparsely pubescent distally with mostly simple trichomes. Cauline leaves 0. Racemes 3-12(-18)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, hirsute as stem. Fruiting pedicels ascending, straight, 2-6(-8) mm, hirsute as stem. Flowers: sepals oblong, 2.5-3 mm, hirsute, (trichomes simple and stalked, 2-4-rayed); petals white, spatulate, 4.5-6 × 1.5-2 mm; anthers oblong, 0.8-1 mm. Fruits ovate to elliptic, plane, slightly flattened, 4-8(-11) × 2.5-4.5 mm; valves pubescent, trichomes stalked (2-)4-rayed, 0.05-0.5 mm; ovules 8-16 per ovary; style (1.2-)2-4(-4.5) mm. Seeds oblong, 1.4-2 × 0.9-1 mm. 2n = 54.

Flowering Jun-Aug. Limestone outcrops and gravelly soil; of conservation concern; 2900-3600 m; Nev.

Draba jaegeri is superficially similar to D. hitchcockii, a narrow endemic of the Lost River Range in central Idaho. Both species are cespitose perennials with relatively large, white flowers, and a chromosome number (2n = 54) otherwise unknown in Draba (M. D. Windham 2004). Draba jaegeri is readily distinguished from D. hitchcockii by having fruits pubescent with (2-)4-rayed trichomes, styles (1.2-)2-4(-4.5) mm, fruiting pedicels 2-6(-8) mm, and spatulate petals 1.5-2 mm wide. By contrast, D. hitchcockii has fruits pubescent with mostly simple and 2-rayed trichomes (with 3- or 4-rayed ones), styles (0.8-)1-1.7(-2) mm, fruiting pedicels (2-)4-13(-18) mm, and obovate petals 2-3.5 mm wide. Draba jaegeri is known only from the Charleston Mountains in Clark County.


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